Chemical Engineering and Chemical Technology, Imperial College London
Doi
Abstract
Acute Myeloid Leukaemia (AML) is a cancer of hematopoietic stem cells that develops
in the three-dimensional (3-D) niches provided by the bone marrow microenvironment in
vivo. The study of AML has been hampered by the lack of appropriate ex vivo models, which
can mimic this microenvironment. It was hypothesised that the fabrication of scaffolds for the
biomimetic growth of leukemic cells ex vivo could facilitate the study of the disease in its
native 3-D niche. The growth of different leukemic cell lines was first evaluated, namely K-
562, HL-60 and Kasumi-6 on highly porous scaffolds fabricated from biodegradable and
non-biodegradable polymeric materials: poly (L-lactic-co-glycolic acid) (PLGA),
polyurethane (PU), poly (methyl-methacrylate) (PMMA), poly (D, L-lactade) (PDLLA), poly
(caprolactone) (PCL), and polystyrene (PS). These results were compared with two
commercially available scaffolds from BD™ Biosciences. Overall, out of all the scaffolds,
PLGA and PU displayed the best seeding efficiency and leukemic cellular growth, assessed
by MTS assay, scanning electron microscopy and immunohistochemistry. In order to
improve the ex vivo 3-D leukemic cell culture, PLGA and PU scaffolds were coated with
bone marrow extracellular matrix (ECM) proteins, collagen (62.5 or 125 μg/ml) and
fibronectin (25 or 50 μg/ml) and a combination of both proteins: collagen + fibronectin (62.5
+ 25 μg/ml) respectively. Once the abnormal hematopoietic 3-D model was established, a
new model to culture normal hematopoietic cord blood mononuclear cells was studied and
compared. All 3 leukemic cell lines and cord blood cells grew better in PU scaffolds coated
with collagen type I using the low concentration and sustained growth in the absence of
exogenous cytokines. As a result, it was concluded that PU-collagen scaffold could provide a practical model with which to study the biology and treatment of primary AML in an ex vivo
mimicry without the use of animal models
